China will not pull back from its efforts to send astronauts into orbit despite the loss of US space shuttle Columbia on Saturday, a source close to China's manned space programme said yesterday in Beijing.

"The incident will not affect China's manned space programme," he told China Daily. "We'll move on according to our schedule."

The official, who preferred not to be identified, stopped short of specifying when China will launch its first manned spacecraft.

Between November 1999 and January 2003, China tested four unmanned spaceflights, with the last one, Shenzhou IV, considered the biggest dress rehearsal yet for sending Chinese astronauts into space.

President Jiang Zemin, in messages sent separately to his US counterpart George W. Bush and Israeli President Moshe Katsav, said the Chinese Government and its people deeply regretted the disaster and the deaths of Columbia's crew members, including Israel's first astronaut who was on board Columbia.

Jiang said he believed that mankind would make progress in space exploration despite the setback.

Chinese space experts echoed his views, saying the Columbia disaster would not deter further work in the field, although the road was dangerous and difficult.

Chen Maozhang, member of Chinese Academy of Engineering, on Sunday deeply regretted the US space shuttle tragedy.

Chen, also a professor of Beihang University (the original University of Aeronautic and Astronautics Science and Technology in China), said that space exploration was a great cause that would suffer various setbacks.

"But mankind will not give up the dream of space exploration. Facing the setbacks, we need to find out the cause of the accident and make improvements," he said.

Tu Shou'e, a space technology expert at the Chinese Academy of Sciences, said China is still on track to launch its first manned spacecraft.

He said China must learn from the accident to improve its own space programme and "fulfil the Chinese nation's dream of flying to space."

Min Guirong, another astronautics expert at the Chinese Academy of Sciences, said the Columbia space shuttle disaster "would not have a direct impact on China's space programme."

During the test flights, China's Shenzhou series craft were not reused, unlike the US spaceships, he said.

China did not plan to develop spaceships that could be repeatedly used, at least for the time being, because it was not as economical as expected, said Min, who also works at the China Academy of Space Technology.

Students at Beijing's Jingshan School also mourned the loss of the Columbia shuttle, which carried their experiment measuring the effect of weightlessness on the production of silk by silkworms.

Li Taotao, leader of the experiment, said she was saddened by the Columbia tragedy.

However, she said the tragedy would not shake her confidence in space experiments.

"I will work even harder and be more actively involved in space experiment programmes."

Xinhua contributed to this story